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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 | /* SPDX-License-Identifier: GPL-2.0 */ /* * __get_user functions. * * (C) Copyright 1998 Linus Torvalds * (C) Copyright 2005 Andi Kleen * (C) Copyright 2008 Glauber Costa * * These functions have a non-standard call interface * to make them more efficient, especially as they * return an error value in addition to the "real" * return value. */ /* * __get_user_X * * Inputs: %[r|e]ax contains the address. * * Outputs: %[r|e]ax is error code (0 or -EFAULT) * %[r|e]dx contains zero-extended value * %ecx contains the high half for 32-bit __get_user_8 * * * These functions should not modify any other registers, * as they get called from within inline assembly. */ #include <linux/linkage.h> #include <asm/page_types.h> #include <asm/errno.h> #include <asm/asm-offsets.h> #include <asm/thread_info.h> #include <asm/asm.h> #include <asm/smap.h> #include <asm/export.h> .text ENTRY(__get_user_1) mov PER_CPU_VAR(current_task), %_ASM_DX cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ and %_ASM_DX, %_ASM_AX ASM_STAC 1: movzbl (%_ASM_AX),%edx xor %eax,%eax ASM_CLAC ret ENDPROC(__get_user_1) EXPORT_SYMBOL(__get_user_1) ENTRY(__get_user_2) add $1,%_ASM_AX jc bad_get_user mov PER_CPU_VAR(current_task), %_ASM_DX cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ and %_ASM_DX, %_ASM_AX ASM_STAC 2: movzwl -1(%_ASM_AX),%edx xor %eax,%eax ASM_CLAC ret ENDPROC(__get_user_2) EXPORT_SYMBOL(__get_user_2) ENTRY(__get_user_4) add $3,%_ASM_AX jc bad_get_user mov PER_CPU_VAR(current_task), %_ASM_DX cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ and %_ASM_DX, %_ASM_AX ASM_STAC 3: movl -3(%_ASM_AX),%edx xor %eax,%eax ASM_CLAC ret ENDPROC(__get_user_4) EXPORT_SYMBOL(__get_user_4) ENTRY(__get_user_8) #ifdef CONFIG_X86_64 add $7,%_ASM_AX jc bad_get_user mov PER_CPU_VAR(current_task), %_ASM_DX cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ and %_ASM_DX, %_ASM_AX ASM_STAC 4: movq -7(%_ASM_AX),%rdx xor %eax,%eax ASM_CLAC ret #else add $7,%_ASM_AX jc bad_get_user_8 mov PER_CPU_VAR(current_task), %_ASM_DX cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user_8 sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ and %_ASM_DX, %_ASM_AX ASM_STAC 4: movl -7(%_ASM_AX),%edx 5: movl -3(%_ASM_AX),%ecx xor %eax,%eax ASM_CLAC ret #endif ENDPROC(__get_user_8) EXPORT_SYMBOL(__get_user_8) bad_get_user_clac: ASM_CLAC bad_get_user: xor %edx,%edx mov $(-EFAULT),%_ASM_AX ret #ifdef CONFIG_X86_32 bad_get_user_8_clac: ASM_CLAC bad_get_user_8: xor %edx,%edx xor %ecx,%ecx mov $(-EFAULT),%_ASM_AX ret #endif _ASM_EXTABLE_UA(1b, bad_get_user_clac) _ASM_EXTABLE_UA(2b, bad_get_user_clac) _ASM_EXTABLE_UA(3b, bad_get_user_clac) #ifdef CONFIG_X86_64 _ASM_EXTABLE_UA(4b, bad_get_user_clac) #else _ASM_EXTABLE_UA(4b, bad_get_user_8_clac) _ASM_EXTABLE_UA(5b, bad_get_user_8_clac) #endif |